How to encode the filename parameter of Content-Disposition header in HTTP?

Question

Web applications that want to force a resource to be downloaded rather than directly rendered in a Web browser issue a Content-Disposition hea

Answer 1

Just an update since I was trying all this stuff today in response to a customer issue

• With the exception of Safari configured for Japanese, all browsers our customer tested worked best with filename=text.pdf - where text is a customer value serialized by ASP.Net/IIS in utf-8 without url encoding. For some reason, Safari configured for English would accept and properly save a file with utf-8 Japanese name but that same browser configured for Japanese would save the file with the utf-8 chars uninterpreted. All other browsers tested seemed to work best/fine (regardless of language configuration) with the filename utf-8 encoded without url encoding.
• I could not find a single browser implementing Rfc5987/8187 at all. I tested with the latest Chrome, Firefox builds plus IE 11 and Edge. I tried setting the header with just filename*=utf-8''texturlencoded.pdf, setting it with both filename=text.pdf; filename*=utf-8''texturlencoded.pdf. Not one feature of Rfc5987/8187 appeared to be getting processed correctly in any of the above.